Elastic protective corner and tensioning strips for transportable brick packages



July 4, 1967 H. T. MARTIN ETAL ELASTIC PROTECT STRIPS FOR IRA IVE CORNERAND TENSIONING NSPORTABLE BRICK PACKAGES Filed Oct. 18, 1965 lNl/E/VTORS Ho/l/ns/vead 7 Martin Russe/ALGou/d July 4, 1 H. T. MARTIN ETALELASTIC PROTECT IVE CORNER AND TENSIONING NSPORTABLE BRICK PACKAGESSTRIPS FOR TRA 2 Sheets-Sheet 2 Filed Oct. 18, 1965 INVENTORSHal/inshead 7." Mari/ n Russel/JGou/a' United States Patent FORTRANSPORTABLE BRICK PACKAGES Hollinshead T. Martin, Evanston, andRussell J. Gould,

Arlington Heights, 11]., assignors to Signode Corporation, Chicago,Ill., a corporation of Delaware Filed Oct. 18, 1965, Ser. No. 497,050 4Claims. (Cl. 206-65) The present invention relates to a brick packageand has particular reference to a novel transportable banded stack ofbricks which, after it has been assembled, is more stable underconditions of handling, transportation and storage, both at the kiln andin the field, than has heretofore been possible in connection withsimilar brick packages designed for the same purpose.

In recent years a major step toward the efficient and economicalhandling of bricks has been the development of a brick packageconsisting of a number of individual pack units, each of which isencircled by a single peripheral loop of metal strapping, with thevarious pack units being maintained in longitudinal alignment andcontiguity by longitudinally extending corner strips at the four cornersof the package straps are positioned. At one or two locations in thepack, openings for the forks of a lift truck are provided by omitting afew longitudinally aligned bricks and, additionally, before the metalstraps are applied, elongated paper, cardboard or wooden cornerprotectors are folded around the four longitudinally extending cornersof the package to provide L-shape corner strips and these strips aresubsequently confined in place by application of the metal straps. Thesecorner protectors or strips are intended to prevent the metal strapsform cutting into the adjacent corners of the bricks and they also servethe purpose of tying the various pack units together in substantialcont-iguity against longitudinal separation. It is to this general typeof brick package that the present invention pertains.

Although a brick package of the general type briefly outlined above hasmaterially reduced the cost of brick handling, it has not provedaltogether satisfactory from the standpoint of package stability. Wherethe corner strips are formed of paper or carboard, very little, if any,tension can be applied to the strips during their application and, as aconsequence, the unit packs are only loosely maintained in theircontiguous relationship. Although the bricks which comprise any givenunit pack may be tightly banded together, the unit packs which are nottightly held together tend to separate under the slightest provocation,as for example under the joggling influence of the box car, truck orother transportation medium. This is due to the relatively lowelongation factor of ordinary paper or cardboard. Seperation of the unitpacks in the upper regions thereof is particularly prevalent whenconditions of unstable equilibrium arise, as for exemple when a givenbr-ick package is placed upon uneven terrain such as may exist in thefield near a particular scene of brick installation. Placement of such abrick package on a foreign object such as a stone or an extraneous brickfragment may cause such unit pack instability as to rupture one or bothof the upper corner strips in one or more places and effect partialcollapse of the package. An additional limitation that is attendant uponthe use of paper or cardboard as a corner strip resides in the inabilityof such materials to withstand weathering. For this reason, contractorsfrequently provide complete coverage for brick packages which must beleft in the open during inclement weather and they avoid brick erectingoperations during such weather.

about which the various metal- 3,329,262 Patented July 4, 1967 Anequally serious limitation that is attendant upon the use of paper orcardboard as a corner protector resides in the crushability of thesematerials, the corners which they are designed to protect readilycutting through the same when the relatively high binding tension of themetal strap requisite to proper binding is applied, or when it isexceeded by unbalanced forces which arise during handling of thepackage. When this occurs, not only is there likelihood of rupturing therelatively fragile corners but there is the distinct danger of suchcorners, When sharp, cutting through the strap and rupturing the latter,thus releasing all of the bricks in the particular unit pack which thestrap surrounds.

Wooden corner strips are seldom used because they are costly, difficultto fashion and apply, and they are not readily susceptible toprogressive unit pack separation. Furthermore, if they are to beeffective as a corner protector they must be of appreciable thicknessand in such an instance the intervening metal binding strapping materialbetween adjacent corner protectors is maintained spaced from the sidesof the package with a consequent loss of centripetal binding force onthe adjacent bricks.

Due to the above outlined limitations associated with cardboard, paperand wooden corner protectors, considerable attention has recently beengiven to the possible use of various flexible plastic materials whichnot only are moisture proof but which possess a suflicient degree ofelasticity that they may be applied and held in position under tensionso that there will be an appreciable degree of residual tension in eachspan between adjacent metal binding straps tending to draw theassociated adjacent brick packs hard against each other, thus obviatingthe tendency for separation of the packs, especially in the uppperregions thereof, when longitudinal separation forces are applied theretoas heretofore described. As a result of extensive experimentation with awide variety of known plastic materials, no specific material in its rawor unworked condition has been found which is suitable for use in themanner outlined above as a combined-corner protector and tensioningstrip for the unit packs of a brick package. Efforts have thereforeturned to the mechanical and physical working of various plasticmaterials to impart to them the required physical properties wherebythey may effectively serve their required protective and tensioningfunctions. Among the most likely materials for such experimentation havebeen those which are capable of grain orientation such as nylon,polyethylene, polypropylene and polypropylene copolymer, particularlythe latter.

Heretofore the results of extensive experimentation with polypropylenefor corner strip use have not proved altogether satisfactory. Stretchingof rolled sheets of polypropylene has established a moleculargrain-orientation of the material and improved the tensile strengththereof, thus greatly reducing the tendency of such material, when usedas a corner strip, to creep or elongate in time, but the stretchedmaterial exhibits the disadvantage that it is unidirectionally brittleand is not readily bendable in the longitudinal direction of stretchingwithout splitting into ribbons so that it is difficult, if notimpossible, of continuous application to the stacked bricks of a packageby passing the same through a folding die. Such portions of a ribbon asmay withstand the folding operation, when applied as a corner strip, arereadily susceptible to splitting under the binding force of the metalstrapping material and the cutting action of the brick corners.

An additional and serious limitation that is attendant upon the use ofsuch grain-oriented polypropylene material as a corner strip resides inthe extreme susceptibility of the material to unidirectionalwith-the-grain scufiing when frictional abrasive forces in thelongitudinal direction of the strip are encountered. Thus, duringpulling of the strip through the narrow folding die surface-fuzzing ofthe material frequently has clogged the folding die aperture andresulted in ultimate rupture of the strip. Still further, duringtransportation of the brick package, the repeated shifting of the loadon the box car or truck platform has produced a progressive condition ofscuffing resulting in strip rupture.

Rolling of a polypropylene sheet has overcome such unidirectionalbrittleness but only at the expense of lack of tensile strength and,furthermore, the rolled material, having incomplete grain orientationwill elongate in time. Thus, a brick package which apparently is tightat the time of its initial assembly, may assume a condition of loosenessby the time it is put to use in the field.

The present invention is designed to overcome the above-notedlimitations that are attendant upon the construction and use of bothconventional and experimental brick packages and, toward this end itcontemplates the provision of a brick package which employs as a cornerstrip a specially treated polypropylene corner strip of conventionalL-shape cross section and which may be applied by conventional cornerstrip-applying apparatus and methods yet which, when in position in thepackage, possesses all of the physical attributes necessary for itsproper functioning both as a corner protector and as a tensioningmember, including the possession of adequate tensile strength so that itmay elongate within its elastic limit during application to the package,resistance to creeping after application to the package so that it willpermanently maintain the necessary package stability, and ability topass through a folding die without splitting or scuffing. The specifictreatment of the raw polypropylene sheet material by means of which thecorner strip of the present invention is produced forms no part of thepresent invention and it is deemed sufficient to state that by aparticular process involving the simultaneous stretching and rolling ofthe sheet material, followed by a surface searing operation, a strip isproduced which may be described as having an over-all grain orientationwhich extends largely, but not completely in a longitudinal directionand has a small amount of transverse grain orientation, together withthin skin or surface random grain orientation on opposite sides thereof.It has been found that whereas a completely grain oriented strip ofpolypropylene is extremely susceptible to splitting upon bending in onedirection as previously described, a very small percentage of transversegrain orientation will effect the necessary molecular adhesion forbending of the strip in any direction. It also has been found that foreffective resistance to scufiing in all directions a substantial randomgrain orientation is required at the surface of the strip. Statedotherwise, the corner strip employed in connection with the presentbrick package may be said to possess substantial but incompletesub-surface grain orientation with complete or random surfaceorientation, i.e. surface deorientation.

The provision of a brick package such as has been set forth aboveconstitutes the principal object of the present invention. Other objectsand advantages of the invention, not at this time enumerated, willreadily suggest themselves as the nature of the invention is betterunderstood.

In the accompanying two sheets of drawings forming a part of thisspecification, one illustrative embodiment,

of the invention has been shown.

In these drawings:

FIG. 1 is a perspective view of a unit pack of bricks, showing the samesevered from a larger brick package which has been assembled, banded,and longitudinally tensioned by means of elongated plastic corner stripsin accordance with the principles of the present invention;

FIG. 2 is a perspective view of a brick package which is comprised of anumber of the unit packs of FIG. 1;

FIG. 3 is an enlarged fragmentary view of one of th terminal corners ofthe brick package of FIG. 2',

FIG. 4 is a fragmentary perspective view illustrating a preferred mannerof progressively applying the corner strips to the package duringassembly of the latter;

FIG. 5 is a front elevational view of a folding die employed inconnection with application of the corner strip and illustratingschematically the complete folding of the corner strip material duringpassage through the die;

FIG. 6 is a fragmentary perspective view of a length of plastic tapewhich, when creased to right-angle cross section, is suitable for use asa corner strip in accordance with the present invention;

FIG. 7 is a greatly enlarged longitudinal sectional view taken on theline 77 of FIG. 6 and illustrating schematically the molecular structureof the plastic tape of FIG. 6;

FIG. 8 is a transverse sectional view taken on the line 88 of FIG. 6,the view being similarly illustrative of the molecular structure; and

FIG. 9 is a fragmentary side elevational view, schematic in itsrepresentation, illustrating the compressional forces which are exertedupon adjacent brick packs under the influence of the elastic cornerstrips of the present invention.

Referring now to the drawings in detail and in particular to FIGS. 1 to3 inclusive, a typical brick package embodying the principles of thepresent invention has been disclosed in FIG. 2 and designated in itsentirety at 10. The package is comprised of a plurality of individualself-sustaining unit packs 12, one of which is shown in FIG. 1. Thepackage 10 does not deviate appreciably in outward appearance from aconventional brick package and, in the exemplary form which has beenselected for illustration herein, the arrangement is generally cubic andconsists of four of the unit packs 12 arranged in contiguousface-to-face longitudinal alignment. Each unit pack is banded by a metalsteel strap 14 and the various unit packs are held together againstlongitudinal separation in a manner that will be described in greaterdetail presently by longitudinally extending corner protectors or strips16 which are L-shape in transverse cross section and underlie thevarious straps 14. As is customary in connection with similar brickpackages, at selected regions of the package 10 longitudinal rows ofbricks are omitted in stacking the bricks, thus defining openings 18which preferably extend completely through the package and which aredesigned to receive the tines of a fork lift truck by means of which thepackage as a whole may be transported.

The specific dimensions of the individual bricks and their stackeddisposition may be varied but for exemplary purposes herein each unitpack 12 may be considered to be comprised of standard American bricks 20supported on their stretcher sides with the corresponding bricks ofadjacent packs being disposed in end-to-end contiguity. With suchbricks, a stacked arrangement results which is thirteen bricks wide,eight bricks high and four bricks deep, i.e. in the longitudinaldirection of the package.

Although as previously stated, the brick package 10 is conventional inoutward appearance, the inventive corner strips 16 of the presentinvention, when applied in a particular manner, provide a package whichis appreciably more stable than are conventional packages of a similarnature but which employ corner strips of cardboard, paper or wood. Indeveloping the corner strip 16, it has been necessary not only to bearin mind the physical attributes required to produce a satisfactorypackage, but also such additional attributes as are required forcommercial application of the corner strip to the brick stack to producethe package. Among the former attributes are a proper combination oftensile strength, elasticity and creep resistance (i.e. resistance toelongation over a period of time) so that the various unit packs will bedrawn hard against one another when the strip is applied .5 undertension and maintained in contiguity throughout the useful life of thepackage; resistance to shearing under the cutting influence of the sharpbrick edges; ability to cushion the brick edges against the bindingforce of the metal straps so that they will not chip or crumble when thestraps are applied; and resistance to external abrasive forces such asmay take place during transportation and handling of the packages. Amongthe latter attributes are ability to fold without longitudinal splittingwhen a flat strip of the material is progressively passed through afolding die preparatory to shaping the same to angular corner stripconfiguration; and resistance to scufiing so that the strip will notshred in the surface regions thereof when passing through the die andthus cause clogging of the die and ultimate rupture of the strip in thedie aperture. All of these physical properties are necessary to theproduction of a successful brick package inasmuch as a brick packagewhich is entirely satisfactory in service is commercially unacceptableif it cannot be produced economically. Therefore, for a clearunderstanding of the problems involved in the production of theinventive corner strip of the present invention, a preferred method ofprogressive application of the corner strips 12 to a continuous brickstack has been schematically illustrated in FIG. 4.

Briefly, the stacked bricks 20 are intermittently advanced on a liveconveyor assembly 30 (FIG. 4) through a corner strip applying stationS1, a sealing station S2 and a strapping station S3 progressively and inthe order named. At the station S1, the plastic corner strip material isfed from a dispenser 36 in the form of a flat ribbon or tape 38 and ispassed between a pair of drag rollers 40 from whence it passes aroundguide rollers 42 and enters a folding die 44 (see also FIG. Where alongitudinal crease 46 is imparted thereto by forcibly bending thematerial fiat against itself so that the elastic limit of the materialis exceeded at the region of torsional application. Thus, as thematerial emerges from the folding die, its restorative properties causeit to assume the desired right angle configuration as indicated at 48for proper and facile application to the continuously moving brickstack. At its region of application, a spring pressed finger 50 ofconformable right angle configuration presses the continuous angularribbon of material into position along the adjacent corner edge of thestacked bricks.

For each corner strip application there will be a separate dispenser 36,together with its associated strip-applying mechanism. Only one suchdispenser has been shown on the far side of the conveyor 30 in FIG. 4for applying a corner strip to one upper longitudinal edge of the stackbut it will be understood that a similar dispensing arrangement will beprovided on the near side of the conveyor 30 for application of a stripto the other upper longitudinal edge. Similarly, if corner strips are tobe applied to the lower longitudinal edges of the stack, additionallower dispensing mechanism will be provided.

Still referring to FIG. 4, the angular strip material 48 is applied tothe stack under appreciable longitudinal tension and this isaccomplished by periodically indexing the conveyor to bring one of theunit packs 12 into transverse register with a strap feeding chute 52associated with a conventional strap feeding mechanism 54 at the strapfeeding station S2. A length of steel strapping 55 is caused to encirclethe unit pack 12 and, at the strapping station S3, a strapping machine56 serves to apply a seal 58 to the overlapping ends of the encirclingloop of strapping, and to sever the thus applied strap 14 from thesource of strapping, all in the manner of conventional strapping machineoperation. The strap 14, in thus binding the bricks of the unit pack 12together, also captures the various lengths of corner strip material 48which have been applied to the stack and, then, during the nextsucceeding indexing of the conveyor 30, this material is pulledforwardly and placed under tension under the retarding influence of thedrag rollers 40. The operation is repetitive scufiing. Without such and,during the next strapping operation a steel strap 14 is applied to thenext adjacent unit pack 12. Due to the retarding influence of the dragrollers 40), the intervening corner strip material 48 between the twoadjacent straps 14 will have been appreciably elongated so that thetension developed therein will operate to draw the two adjacent unitpacks 12 hard against each other as illustrated by the arrows in FIG. 9.

The thus banded unit packs 12, securely bound to one another by reasonof the tension in the corner strip material 48, are periodicallyadvanced on the conveyor and at a suitable severing station along theconveyor they may be separated into individual packages of four unitpacks each or any other desirable unit pack multiple. Due to thethermoplastic nature of the corner strip material 48, severing of thepackages from the stack may be accomplished by the use of a suitableCalrod type burning tool. Upon severing of the strips 48 a completedpackage including the coextensive corner strips 16 results.

Considering now the physical properties of the plastic material employedin the production of the corner strips 16, it has been found that asheet of polypropylene copolymer when subjected to a simultaneousstretching and rolling operation, followed by a surface searingoperation, will produce a sheet of material which, when divided intoribbons of a suitable width for corner strip application, possessesphysical properties of an unusual nature enabling the same to be appliedin the manner previously indicated to a brick stack whereas, hitherto,successful application of numerous other plastic ribbons has not beenattained despite much experimentation. A fragment of such a ribbon hasbeen illustrated in FIGS. 6, 7 and 8 and it may be regarded as being ashort length of the ribbon 38 associated with the dispenser 36 of FIG.4. The dimensions of the ribbon 38 are not critical within reasonablelimits but it has been found that a ribbon which is one inch in widthand which has a thickness of 0.02 inch is entirely suitable for cornerstrip construction.

As shown in FIGS. 7 and 8, the aforementioned simultaneous rolling andstretching operation which is performed upon the raw polypropylenecopolymer imparts to it a molecular orientation 60 which is largely butnot entirely unidirectional in the direction of stretching. Because theribbon has such predominant longitudinal orientation, its tensilestrength is greatly increased and its tendency to creep, i.e. toelongate after a period of time when under tension, is materiallyreduced. A slight amount of cross-orientation 62 is allowed to remain inthe ribbon and this is sufficient to permit complete folding of theribbon when it passes through the folding die 44 of FIG. 5. Unorientedpolypropylene is, of course, amenable to folding in any direction but itlacks tensile strength and it is highly susceptible to creeping. It hasbeen found however that a very slight amount of cross-orientation in thematerial will'sufifice to allow longitudinal folding of the ribbon.

In the treatment of the polypropylene material, after such predominantlongitudinal molecular orientation has been imparted to it, the oppositesurface regions of the material are caused to become completelydeoriented as indicated at 64 and this may be effected by a surfacesearing operation, utilizing a flame or searing rolls. Molecularlyoriented polypropylene is highly susceptible to unidirectional surfaceabrasion or scufiing in the direction of orientation although it isalmost entirely resistant to such scufling in a transverse direction.The slight amount of cross orientation indicated at 62 has a negligibleeffect as a deterrent to scufiing and, for resistance to scufling in alldirections, a completely deoriented material is required. The randomsurface orientation indicated at 64 thus affords this resistance todeorientation of the ribbon at its surface regions, the friction whichis developed as the ribbon passes through the folding die 44- willcreate a condition of surface fuzzing which rapidly clogs the dieaperture and leads to ultimate rupture of the ribbon. Additionally, whenthe brick package is in the process of being transported in a truck orflat-car, the joggling action which is encountered incident to a roughterrain or due to acceleration and deceleration of the vehicle willpermit limited shifting of the package without any deleterious scufiingaction. The random surface orientation indicated at 64 offers additionaladvantages which render the ribbon suitable as a corner strip material.One such advantage is that it augments the action of the aforementionedcross-orientation in inhibiting splitting of the material when it isfolded longitudinally. When any material becomes split due to a foldingor bending action, the critical region is at the apex of the bend. Thus,with a completely deoriented surface region available at the apex of thefold when the material is passing through the folding die 44, thiscritical region is reinforced and the initial microscopic crevice whichinitiates the splitting of most solid materials does not take place. Athird advantage oifered by complete surface deorientation of the ribbonresides in an appreciable increase in the slip-efficiency of the ribbon.This slip-eificiency is related to the aforementioned resistance toscufiing but it also presents the further and distinct advantage thatthe coefficient of friction between the metal binding strap and theplastic material of the corner strips 16 is appreciably reduced so thatthe strap, during tensioning thereof, will slide around the variouscorners afforded by these strips and distribute its tensioning effectmore uniformly around the periphery of the package.

It will be appreciated that brick arrangements other than the specificarrangement herein illustrated are capable of being packaged accordingto the present invention. For example, although the bricks in each unitpack 12 are arranged in side-by-side relationship while the bricks inadjacent unit packs are disposed in end-toend relationship, a reversearrangement of bricks may be resorted to in which the unit packs arebanded by steel straps which pass over the ends of the individual bricksand in which the corner strips 16 overlie such ends. Therefore in theappended claims the term end-toend is to be broadly constructed asrelating to the faces of the bricks which meet in contiguity and extendtransversely of the brick stack on the conveyor. Similarly, the termside-by-side is to be broadly construed as relating to the faces of thebricks which meet in contiguity and extend longitudinally of the stack.The invention is therefore not to be limited to the exact arrange mentof parts shown in the accompanying drawings or described in thisspecification as various changes in the details of construction may beresorted to without departing from the spirit of the invention.Modifications may thus be resorted to within the scope of theaccompanying claims.

Having thus described our invention, What We claim and desire to secureby Letters Patent is:

1. A packaging component for rectangular brick packages of the typeconsisting of separable brick packs disposed in side-by-side contiguity,each pack being banded by a steel strap, said packaging componentcomprising: an elongated moisture-impervious abrasion-resistant cornerprotector and tensioning strip assuming an L-shape cross section andadapted to overlie one longitudinal corner edge of the package and toextend under tension between and beneath adjacent steel straps, saidstrip being formed of a molecularly orienta-ble heat-fusiblethermoplastic polymer having the inner portion thereof set with amolecular orientation which is largely longitudinal but which presentssufficient transverse molecular orientation to enable the strip to befolded longitudinally without spliting, and having sufficient resistance to elongation-in-time that it will not stretch under suchseparation forces as may be encountered by adjacent bricks when thepackage is handled, and having outer surface portions which are fused toa depth of between one and three mils so as to impart abrasionresistance to the strip as a whole.

2. A packaging component as set forth in claim 1, wherein saidmolecularly orientable thermoplastic polymer is polypropylene.

3. A packaging component as set forth in claim 1, wherein saidmolecularly orientable thermoplastic copolymer is polyethylene.

4. A packaging component as set forth in claim 1, wherein saidmolecularly orientable thermoplastic polymer is nylon.

References Cited UNITED STATES PATENTS 3,003,296 10/1961 Feldkamp et al.206-46 3,148,773 9/1964 Baumer 20646 3,150,854 9/1964 Jamieson 248345.l

OTHER REFERENCES Modern Plastics, pp. 166, 167 (10/19/63).

THERON E. CONDON, Primary Examiner.

J. M. CASKIE, Assistant Examiner.

1. A PACKAGING COMPONENT FOR RECTANGULAR BRICK PACKAGES OF THE TYPECONSISTING OF SEPARABLE BRICK PACKS DISPOSED IN SIDE-BY-SIDE CONTIGUITY,EACH PACK BEING BANDED BY A STEEL STRAP, SAID PACKAGING COMPONENTCOMPRISING: AN ELONGATED MOISTURE-IMPERVIOUS ABRASION-RESISTANT CORNERPROTECTOR AND TENSIONING STRIP ASSUMING AN L-SHAPE CROSS SECTION ANDADAPTED TO OVERLIE ONE LONGITUDINAL CORNER EDGE OF THE PACKAGE AND TOEXTEND UNDER TENSION BETWEEN AND BENEATH ADJACENT STEEL STRAPS, SAIDSTRIP BEING FORMED OF A MOLECULARLY ORIENTABLE HEAT-FUSIBLETHERMOPLASTIC POLYMER HAVING THE INNER PORTION THEREOF SET WITH AMOLECULAR ORIENTATION WHICH IS LARGELY LONGITUDINAL BUT WHICH PRESENTSSUFFICIENT TRANSVERSE MOLECULAR ORIENTATION TO ENABLE THE STRIP TO BEFOLDED LONGITUDINALLY WITHOUT SPLITING, AND HAVING SUFFICIENT RESISTANCETO ELONGATION-IN-TIME THAT IT WILL NOT STRETCH